A Joke Too Far
by D2DM-FanFic
Summary: Underfell Sans x Underfell Frisk Fan Fic. It will contain: sex, bondage, dirty talk, biting, blood, magic tentacles, swear words, pregnancy, S/M. I write in a second person/Insert POV and I switch POV through out the story. Takes place in UnderFell AU, the barrier is not broken, Frisk as lived with the skelebros for years. It's April 1st and Frisk plays a mean prank on Sans.


THIS IS A RATED M - FOR MATURE AUDIENCES ONLY - UNDERFELL AU SANSXFRISK FAN FIC

It will contain: sex, bondage, dirty talk, biting, blood, magic tentacles, swear words, pregnancy, S/M.  
I write in a second person/Insert POV and I switch POV through out the story. Takes place in UnderFell AU, the barrier is not broken, Frisk as lived with the skelebros for years.

If you do not like any of the above mentioned things please do not read, there is no reason to spread hate.  
As far as this story goes, it uses my head canon that Skeleton monsters are not just animated human skeletons, so they breathe, can kiss and can feel.

Your breathing is hard as you sprint through the woods, dodging trees and bushes as you run. Your heart is hammering in your chest as you go and you decide to look back. You catch a glimpse of white blur by your glasses, just a hair away from smashing into your face. With a small yelp, you return your gaze forward just in time to jump over a creek you would have fallen into. _That was a close one._

You see another white blur wiz past you and hear it pierce into a tree a head of you. As you run the tree by you see a bone jutting out of it and try to pick up your pace some more. You feel the strain in your legs as you push them harder, your muscles willing you to stop. A loud chuckle can be heard from behind you and you look back again but see nothing but the forest. Thinking you were just hearing things you turn to look back in front of you. _Smack._

"boo." You're stopped in your tracks as you slammed into something large and bounce back almost losing your balance. Another low chuckle fills your ears and you look up at the face smiling down at you. Sparing no more time you turn on your heels and run. The ache in your legs is ever growing and slowing down your sprint. Another bone is shot into a tree near by your left side, so you direct your run right. Now to your right, so you run more towards the left. Another chuckle, you look back again.

"stop!" as the words reach your ears, you see a cliff appear before you and try to skid to a stop before the edge. Your body's momentum from your sprint doesn't allow you to catch your balance before the end and you feel your weight start to drop.

"AH!" You feel your soul leap out of your chest as you flail your arms around in a desperate attempt to stop yourself. As you're falling something warm catches your ankles and causes your body to swing, going from falling legs first to head first. There's enough force to make you loose your glasses but you manage to push them back to your face and catch a glimpse of what's holding you. A tentacle works it's way around legs and up your torso and arms. Once you were fully wrapped you realize you had stopped falling; and the tentacle around you had limited your movements entirely, not that you had anywhere else to go though.

You're lifted up and back over the edge of the cliff as two red sneakers walk towards you. A hearty laugh fills your ears as you look up towards the figure.

"looks like my trap caught a little mouse." the tip of the tentacle is now rubbing against your check near your ear, and you giggle at it. "you didn't last nearly as long this time." he looks grumpy, eyes glowing red.

"Yeah I noticed." you sighed.

"you need to stop looking back as you run." the disappointment in his voice is apparent. "if i didn't keep bringing your attention back to in front of you, you would have gotten hurt." Thinking back on it, he was right; each time you looked back he did something to make you look forward again. "not to mention running off a cliff."

"Well I can't help it," you pout, "when I hear your laugh it makes me want to see your face." you watch a small red blush creep onto his cheekbones. He's so cute when he blushes like that, but you'd never dare say so. You've been upside down for too long now and can feel the blood that has rushed to your head making you light headed. You try to move against your restraints.

"something wrong dollface?" he notices your movement but doesn't try to help.

"I kind of don't want to be upside down anymore." a smirk lines his face.

"what? don't wanna _hang_ around with me anymore?" The magic around you tightens.

"Sans." you reply sternly, he knows what you meant.

"yeah?" the smirk on his fangs growing with your impatience.

"Come on, let me go now." You see a flicker in his eyes.

"i don't know dollface, you lost our little game." a red tongue runs over his fangs, "not exactly in a position to be barking orders. in fact, there should be a punishment for the loser." _Oh great, he probably had this planned from the start._ You're starting to get woozy, you need to think fast.

"I agree with you." he raises a brow, "I lost our game and deserve your punishment." that blush grows a little darker and his tongue flicks over his teeth again. "But it wont feel like much of a punishment if I'm not awake for the whole thing right?" Looks like he's thinking about it, "So if I stay upside down like this, I'll pass out and miss out on the punishment." you playfully pout your lips. "Punishing me just wouldn't be the same if I'm unconscious during it right?" His expression shows that he's still thinking about it and lets out a laugh.

"i could still have fun punishing you while you're unconscious." his eyes are half lidded now and you can tell he's actually thinking of letting you pass out. Your vision is starting to go, you're running out of time. _Plan B._

" _Oh, please, Sansy_ " you say in your most helpless tone of voice you can muster, "I want, no _need_ to experience your punishment." you slowly flutter your eyes and nibble on your lips. His face grows redder and his mouth opens a bit. _Good, it's working so far, just a little more._ "How will I learn to be better," his interest is growing. _Hook._ "if you don't teach. me." his smile growing wider. _Line._ "properly?" your words slow and you try pronouncing them thoroughly with a low seductive tone, to make your point clear.

You see a bright flash and feel your stomach twist into a knot before you realize you're no longer upside down and you're in Sans's room. _And Sinker._ Sans is in front of you again, a satisfied grin on his face; you try to hide yours. You go to caress his cheek and find out you're still bound by his magic. He snickers in your face.

"didn't really think you were going to be let go that easily did ya?"

"Of course not, but I was hoping it'd be a _hands on_ experience." You move against the magic restraints to play off your pun. You're rewarded with a hearty laugh and a large grin. Sans leans towards you, his mouth near your ear.

"don't worry, dollface, i'll make sure you stay awake this time so you can experience every little part." His voice is a husky whisper and his breath tickles your ear; you shiver involuntarily. "mmm.. that's right honey, your body is already anticipating what i'm going to do to you..." he slowly runs runs the tip of his finger up your jawline to your other ear. He hooks his fingers behind the end of your glasses before carefully removing them. "we don't want to break these again, so let's get rid of them now." You let out a small whimper as your vision blurs without your glasses.

"now, now, don't pout. you don't need to see, you only need to feel." Sans leans into you and presses a gentle kiss onto your lips and you return it to his. His fangs nibble along your bottom lip before pinching it between his teeth and pulling your lips apart. You let out a soft moan and you hear him hum in response. Once his mouth releases your lip, you go to bring them together again only to be met with a sharp bite. "leave it open." Sans growls at you.

Obeying his order you keep your mouth open for him while he licks at your lips. His tongue tracing around before dipping inside and crossing over your tongue. It swirls around your mouth exploring around your teeth before coming back to tightly wrap around your tongue and pull it as much as possible from your mouth. The appendage proceeds to twist and slide up and down while continuously pulling. You moan into his mouth and feel the magic around you tighten again.

He seems to be enjoying playing with you, not that you mind too much, though you were hoping for a bit more. You move around and try to speak to ask for what you wanted but can only mumble around his tongue. He pulls away.

"who said you could talk?" hearing the annoyance in his voice, you want to quip back he never said you couldn't talk; but you know better. His tongue pulls away and the magic surrounding you moves to place you in a new position. Resting on your hands and knees with your ass facing him, he chuckles lightly and you watch a tentacle slither around pulling up your sweater to expose your legging covered rear. "y'know i heard that tonight," the magic works its way into the waist band of the leggings and your panties; pulling them down to your thighs. "there'd be a full moon!"

He laughs loudly and you muffle your own so as not to upset your silence. His magic softly roams the skin, caressing the curves before pulling away. You start to miss the contact but not for long, as it quickly whips down onto your flesh.

"AH!" you yelp out from the sudden touch. The string slowly starts to fade when you're hit with another slap. This time the tentacle lingers longer and wraps around your cheeks and squeezes before releasing it again.

"you need to eat more hot dogs dollface," another spank "not enough jiggle here." he pouts and you chuckle a little too loudly. "somethin funny?" he asks, not amused.

"It's just that, Paps wouldn't let me eat more of them even if I wanted to. Plus, with all the training you two make me do, I can't seem to gain much weight at all." The appendages restraining you move around and tighten.

"i don't know bout that, you feel a bit plumper to me." you frown, not exactly what you want to hear right now.

"Sans," you whine and wiggle around "forgetting something?" he takes you hint and repays you with another hard spank. You moan out, being able to feel how red your skin is turning.

"not really," he repeats the action and chimes "such a lovely shade~ almost matches the red on your face." One of the magic tentacles turns your face towards his and he smirks while admiring your complexion. "can't help but wonder how it'd look if i did this-" the appendage that had been spanking you now swirls around between your labia lips. It was warm and smooth, effortlessly sliding around your entrance and clit. You buck your hips, first away from how sudden it was but then with it, matching its movements to increase the pleasure. It felt great and you weren't afraid to show it.

"good kitten." It's a different pet name but you play along and give him a pleasant purr. He laughs, "well then guess it's time i play with my pussy properly." All at once it plunges inside you filling you up. It twirls inside feeling all around your inner walls, trying to expand as it goes.

"Oh- S-Sans!" you moan out loudly, bucking into it, wanting more from him. The magic withdraws and enters at a slower pace, a little too slow for your liking. "Hah.. isn't this a bit gentle and slow for a punish-" a different tentacle forces its way into your mouth, cutting off your sentence.

"you don't get to decide that." he barks at you, obviously not liking you telling him what to do. The magic inside you pulls out; leaving only your mouth filled. He moves behind you, adjusting himself to a good angle before harshly thrusting himself in. You yell out around the tentacle in your mouth before turning towards him to shoot him a glare. He smirks and shrugs before pulling out slowly and harshly thrusting in again. "still too gentle dollface?"

 _If that's how he wants to play..._ you start to bite and lick around the magic appendage in your mouth changing firmness from soft to hard; knowing he can feel everything it feels. You listen to his low moans behind you, feeling a bit satisfied with yourself.

"ooh... you're really asking for it aintcha?" He dismissed the magic binding you and roughly turns you over to face him; pulling his face close to yours before pushing his lips hard onto yours in a rushed pace. You try to return all the kisses but need to pull back to breathe. Sans grabs the back of your head and pulls you towards him again causing you to just gasp for air over his lips instead. He takes advantage of your parted lips and slips his tongue inside your mouth again, exploring with ease.

He picks up the pace of his thrusts, making them uniform in speed and roughness. You're loving the feeling of being so connected to him; doing your best to watch his expression, sweaty and flushed. It's a great look for him and it only heightens your arousal. The ruthless pounding is starting to build you over fast and judging from the moans and gasps from Sans he wouldn't last much longer either. A few more slams against your walls and you come toppling over your climax. Your hips twitching with the waves of pleasure that wash through you.

"hey... now..." he grunts at you redirecting your hips for himself, "who said- ya could finish, huh?" you can tell he was trying to be stern but it just didn't come across between moans.

"Oh, s-sorry" you manage between gasps while slowly descending from the high of your orgasm, "c-couldn't help- you are too good-" Sans cuts you off again by slamming his face into yours for another round of hard kisses, ending with him moaning into your mouth. A few more hard thrusts and you feel him release inside you. The hot fluid leaks out while he rides out his orgasm, making sure he got everything he wanted before pulling out.

He plops his weight on top of you and you're left laying there a wet mess. Once you regain your breathing you lightly push on his shoulder.

"Hey, let's go get cleaned up." he doesn't answer so you adjust to look at him. His eyes are shut and his mouth is slightly parted with drool and soft snores spilling out. You laugh quietly before carefully pushing him off so you could go shower.

You walk back into the bedroom with a towel wrapped around you and one for your hair. Quietly, as to not wake up Sans, you close the door. While walking over to the dresser to grab something to sleep in, you glance at the calendar sitting on top; March 31st. Realization hits you hard, tomorrow is April 1st - April Fool's Day!

You groan aloud, Sans was going to be obnoxious the whole day with stupid pranks and jokes. You wouldn't be surprised if you didn't see Papyrus at all. _If only there was a way to show him how it felt._ Suddenly an idea hits you, this year will be different, this year you'll prank him so great he'll never forget it! You look over at your sleeping boyfriend and smirk. You throw on a sweater and a pair of boots and make your way to the dump to set your plan in motion.

It's quiet when you wake up, you glance over to Sans, who is still sleeping besides you. You use your pillow to replace your spot on the bed; he snuggles up to it immediately and you smile. _So cute!_ Never the less you set to work on your prank, going over to pull out the cleaned pregnancy test you found at the dump. It took you awhile to find a positive test, but it will be worth it.

You chuckle deviously. _Time to wake the sleeping beauty~_ while facing away from the bed you take a deep breath.

"Oh no!" you shout just loud enough to startle Sans awake. He pops out of the bed, ready for an attack and rushes over to you.

"what!" he exclaims obviously on alert. You force a straight face.

"Well I hadn't been feeling well these past mornings, so I decided to take this test." You extend the test towards him and he takes it to look for himself. "Sans, I'm pregnant." You fight back your laughter as you watch him.

"wha...?" His eyes widen and his whole body freezes. _Revenge will be mine._


End file.
